On 6/11/20 4:33 PM, John Garry wrote:
Yes, I do think I would prefer updating sbitmap_bitmap_show() to accept a filter. Especially as Ming Lei has now updated the tag iterators to accept a filter, too, so it should be an easy change.+static int hctx_tags_shared_sbitmap_bitmap_show(void *data, struct seq_file *m)+{ + struct blk_mq_hw_ctx *hctx = data; + struct request_queue *q = hctx->queue; + struct blk_mq_tag_set *set = q->tag_set; + struct sbitmap shared_sb, *sb; + int res; + + if (!set) + return 0; + + /* + * We could use the allocated sbitmap for that hctx here, but + * that would mean that we would need to clean it prior to use. + */*+ res = sbitmap_init_node(&shared_sb, + set->__bitmap_tags.sb.depth, + set->__bitmap_tags.sb.shift, + GFP_KERNEL, NUMA_NO_NODE); + if (res) + return res; + sb = &shared_sb; + + res = mutex_lock_interruptible(&q->sysfs_lock); + if (res) + goto out; + if (hctx->tags) { + hctx_filter_sb(sb, hctx); + sbitmap_bitmap_show(sb, m); + } + + mutex_unlock(&q->sysfs_lock); + +out: + sbitmap_free(&shared_sb); + return res; +} + static int hctx_tags_bitmap_show(void *data, struct seq_file *m) { struct blk_mq_hw_ctx *hctx = data;@@ -823,6 +884,7 @@ static const struct blk_mq_debugfs_attr blk_mq_debugfs_hctx_shared_sbitmap_attrs{"busy", 0400, hctx_busy_show}, {"ctx_map", 0400, hctx_ctx_map_show}, {"tags", 0400, hctx_tags_show}, + {"tags_bitmap", 0400, hctx_tags_shared_sbitmap_bitmap_show}, {"sched_tags", 0400, hctx_sched_tags_show}, {"sched_tags_bitmap", 0400, hctx_sched_tags_bitmap_show}, {"io_poll", 0600, hctx_io_poll_show, hctx_io_poll_write},Ah, right. Here it is.But I don't get it; why do we have to allocate a temporary bitmap and can't walk the existing shared sbitmap?For the bitmap dump - sbitmap_bitmap_show() - it is passed a struct sbitmap *. So we have to filter into a temp per-hctx struct sbitmap. We could change sbitmap_bitmap_show() to accept a filter iterator - which I think you're getting at - but I am not sure it's worth the change. Or else use the allocated sbitmap for the hctx, as above*, but I may be remove that (see 4/12 response).
Cheers, Hannes -- Dr. Hannes Reinecke Teamlead Storage & Networking hare@xxxxxxx +49 911 74053 688 SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg HRB 36809 (AG Nürnberg), Geschäftsführer: Felix Imendörffer
